The invention relates to apparatus for cleaning of curved surfaces employing the cloth principle.
It is known e.g. from German patent No. 300 5469-02 in apparatus for cleaning by employing the cloth principle that the cleaning cloth is brought in operating contact with the surface to be cleaned by a pressing element having an elastic rubber membrane. This rubber membrane can be expanded by a pressure medium and the cleaning cloth is guided to the surface that is to be cleaned.
It is also known to design the pressing element for the cloth as a functional unit and to provide the side pointing to the surface to be cleaned with an elastic build-up. This pressing element can be slid by a pneumatic actuator and can be so engaged to or disengaged from the corresponding surface to be cleaned.
These kinds of cleaning apparatus have means to pull off the cleaning cloth from the roll for the unsoiled cloth, as well as means to roll up dirty cleaning cloth on the roll for the soiled cloth. These kinds of apparatus also are provided with means to insure that a constant cleaning cloth length is pulled off from the roll for the unsoiled cloth. For this purpose, for example according to the aforesaid German patent No. 300 5469-C2 the diameter of the roll for the soiled cloth is sensed and a mechanical control limits the rotational angle of the driven roll for the soiled cloth as a function of that diameter.
It is also known to use angular encoders at the cloth rolls to provide identical cloth lengths and to retain identical cloth lengths for cleaning by pulling off and rolling up.
The systems for pulling off and rolling up the cloth, and for securing identical cloth lengths are usually quite costly, and require considerable space which is especially in the case of sheet fed offset presses not readily available.
It is an object of the present invention to provide an apparatus for cleaning curved surfaces by the cloth principle with simple means and low space requirements.
Apparatus for cleaning a curved surface by employing the cloth principle, the apparatus having a roll for unsoiled cloth with unused cleaning cloth there, a roll for soiled cloth for taking up used soiled cloth, a pressing element for pulling unsoiled cleaning cloth off the roll for unsoiled cloth and to bring it in contact with a surface to be cleaned by a movement of the element toward the surface, and means for pulling cleaning cloth off the roll for unsoiled cloth and for rolling soiled cloth that is longer or equal to the part thereof that is removed by the pressing element from the roll for unsoiled cloth independently of the respective diameters of the rolls for soiled and unsoiled cloth.
The solution of the present invention establishes by simple means equal cloth lengths rolls taken independently from the diameter of the roll of unsoiled cloth or the roll of soiled cloth and rolled up on the roll of soiled cloth. The pulling off of cleaning cloth with the pressing element furthermore permits space saving and cost reduction.